Vehicle-mounted block heater cord extender with extendable arm and wireless warning unit

ABSTRACT

A block heater cord extender features a frame for mounting to a vehicle, a female electrical socket carried on the frame for receiving a male plug of the vehicle&#39;s block heater cord, and an extendable/retractable arm having a proximal end movably mounted to the frame. The arm is extendable and retractable in length, and carries an electrical plug at its distal end for mating with a mains power electrical outlet. Circuitry of the extender includes a wireless transmitter arranged activated by the mains power supply when the extender is plugged in. The transmitter sends a signal to a separate warning unit placed inside the vehicle, which reminds a vehicle operator to unplug the extender before driving away.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit under 35 U.S.C. 119(e) of U.S.Provisional Application No. 62/573,977, filed Oct. 18, 2017, theentirety of which is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to vehicle-mountable devices forextending the reach of a vehicle's block heater cord and eliminating theneed to carry an extension cord in the vehicle and retrieve the cordfrom the vehicle cabin every time the block heater is used.

BACKGROUND

In cold climates, vehicle block heaters keep the engine warm and makethe vehicle easier to start, thereby reducing stress on the battery,starter, and the engine itself. A standard block heater has only a shortpower cord intended to route the power plug of same to a location nearthe front end of the engine compartment, where a separate extension cordcan be connected to extend the power cord to an electrical outlet of amains power supply.

Historically, block heaters have been plugged into a power receptacle byretrieving an extension cord that is stored in the vehicle. Two handsare needed to first plug the block heater power cord into the extensioncord, and then the extension cord into the mains power electricaloutlet. This can be especially challenging in cold weather. Some driversleave their block heater plugged into the extension cord, and wrap theextension cord around their side-view mirror, while others have mounteda coiling bracket on the front of their vehicle around which theymanually wrap their extension cord manually to facilitate easierplugging in of their block heater.

Previously, it has been proposed to simplify the process by mounting acompact extension cord reel to an exterior of the vehicle and leavingthe block heater power cord permanently plugged into the reel, so thatan appropriate length of cord can be selectively deployed from the reelwhenever needed, and later easily or automatically retracted onceunplugged.

U.S. Pat. No. 5,803,216 discloses such a reel-based block heater cordsolution, which further incorporates a timer function for automaticactivation and deactivation of the block heater according to aprogrammed schedule.

U.S. Pat. No. 6,854,575 discloses another reel-based block heater cordsolution, and incorporates a warning light to remind the user that theblock heater is plugged in before driving away. However, the warninglight is situated on the reel housing of the unit, which is externallymounted to the vehicle at a front license plate holder thereof, andtherefore may be overlooked, particularly if the driver approaches theparked vehicle from the side or rear.

Despite the forgoing offerings in this field, there remains room forimprovements or alternatives, and Applicant has a designed a uniquesolution, the details of which are outlined in the following disclosure.

SUMMARY OF THE INVENTION

According to a first aspect of the invention, there is provided a blockheater cord extender for connecting a power cord of a vehicle's blockheater to an electrical outlet, said extender comprising:

a frame for mounting to the vehicle;

a female electrical socket carried on the frame for receiving a maleplug of the power cord of the vehicle's block heater;

an arm having a proximal end movably mounted to the frame, and a distalend situated opposite the proximal end, the arm being extendable andretractable to expand and reduce an overall length of said arm betweenthe proximal and distal ends thereof;

an electrical plug carried on the arm at or proximate the distal endthereof, said electrical plug being configured to mate with anelectrical outlet of a mains power supply; and

a circuit comprising electrical conductors connected between the femaleelectrical socket and the electrical plug to enable transmission ofpower between the mains power supply and the block heater when the powercord of the vehicle's block heater is mated with the female electricalsocket of the extender and the electrical plug of the extender is matedwith the electrical outlet of the mains power supply.

Preferably the arm is movable between a storage position retractedagainst or adjacent the frame and a deployed position reaching outwardlyfrom the frame.

Preferably the arm is pivotable about two different axes for bothelevational and lateral positional adjustment of the arm, by which auser can aim the distal end of the arm toward the electrical outlet ofthe mains power supply.

Preferably the electrical plug is carried on the arm by a flexible cord.

Preferably said flexible cord is extendable and retractable from thedistal end of the arm.

Preferably said flexible cord carries a pair of electrical contacts atan internal end thereof disposed inside a hollow interior of the arm,and the conductors comprise a pair of conductive strips defined withinthe hollow interior of the arm along which the pair of electricalcontacts are slidable under pulling or pushing of the flexible cord fromor back into the hollow interior of the arm.

Preferably the arm comprises multiple sections engaged together in asliding manner for sliding extension and retraction of the sectionsrelative to one another in a longitudinal direction of the arm, and theelectrical conductors comprise, for each pair of adjacent sections, aconductive strip lying in the longitudinal direction on one of saidadjacent sections and a respective electrical contact carried on theother of said adjacent sections in sliding contact with said conductivestrip.

Preferably the electrical conductors comprise, for said each pair ofadjacent sections, a second conductive strip on said one of the adjacentsections, and a second electrical contact and said other of the adjacentsections.

Preferably both of said conductive strips are defined on opposingsurfaces of said one of said adjacent sections, and both of saidconductive contacts project from opposite sides of the other of saidadjacent sections.

Preferably each conductive strip is recessed in a groove.

Preferably each conductive strip is located internally of said one ofsaid adjacent sections.

Preferably there are arm supports projecting from the frame to supportthe arm when stowed against or adjacent the frame.

Preferably the arm comprises a plurality of telescopically matedsections by which telescopic collapse and extension of said sectionsadjusts the overall length of the arm.

Preferably there is provided a separate warning unit for placementinside the vehicle, wherein the circuit comprises a wireless transmitterarranged to be activated by the mains power supply when the electricalplug is connected thereto, and the separate warning unit comprises awireless receiver for receiving an output signal from the wirelesstransmitter, and a warning indicator activated by receipt of said outputsignal to warn a vehicle operator that the block heater cord extender isplugged into said mains power supply.

According to a second aspect of the invention, there is provided a blockheater cord extension system for connecting a power cord of a vehicle'sblock heater to an electrical outlet, said system comprising:

a block heater cord extender comprising:

-   -   a frame for mounting to the vehicle;    -   a female electrical socket carried on the frame for receiving a        male plug of the power cord of the vehicle's block heater;    -   an extendable/retractable extension carried by the frame;    -   an electrical plug carried on the extension and configured to        mate with an electrical outlet of a mains power supply;    -   a circuit comprising electrical conductors connected between the        female electrical socket and the electrical plug through the        extendable/retractable extension to enable transmission of power        between the mains power supply and the block heater when the        power cord of the vehicle's block heater is mated with the        female electrical socket of the extender and the electrical plug        of the extender is mated with the electrical outlet of the mains        power supply; and    -   a wireless transmitter installed in the circuit for activation        by the mains power supply when the electrical plug is connected        to said mains power supply; and

a separate warning unit for placement inside the vehicle and comprisinga wireless receiver for receiving an output signal from the wirelesstransmitter when activated, and at least one warning indicator activatedby receipt of said output signal to warn a vehicle operator that theblock heater cord extender is plugged into said mains power supply.

Said at least one warning indicator may comprises an indicator light.

Additionally or alternatively, said at least one warning indicator maycomprise an audible alarm.

BRIEF DESCRIPTION OF THE DRAWINGS

One embodiment of the invention will now be described in conjunctionwith the accompanying drawings in which:

FIG. 1 is a front elevational view of a block heater cord extenderaccording to the present invention with an extendable/retractable armthereof in a collapsed and stowed position.

FIG. 2 is a front elevational view of the block heater cord extender ofFIG. 1 with the extendable/retractable arm thereof in a deployed, butstill collapsed, position.

FIG. 3 is a front elevational view of the block heater cord extender ofFIG. 2 with the extendable/retractable arm thereof in a deployed andextended position.

FIG. 4 is an elevational view of a separate warning unit for informing adriver when the block heater cord extender is plugged into a mains powerelectrical outlet.

FIG. 5 is a cross-sectional view of the extendable/retractable arm ofthe block heater cord extender of FIG. 3.

DETAILED DESCRIPTION

The block heater cord extender 10 illustrated in the accompanyingdrawings features a frame 12 mountable to the exterior of a vehicle, anda telescopically extendable/retractable arm 14 coupled to the frame by amulti-directional joint 16 by which the arm 14 can swing laterallytoward and away from the frame about an upright pivot axis, and alsoelevationally upward and downward relative to the frame in order topoint the lateral arm in any of a number of different directions fromthe frame. Together with longitudinal extension/retraction capabilitiesof the telescopic arm, this enables a user to move a distal end 14 a ofthe arm anywhere within a notable range of three dimensional space infront of the frame in order to aim the distal end 14 a of the arm towardan electrical outlet of a mains power supply so that an electrical plug18 carried on the arm 14 near the distal end 14 a thereof can be matedwith the electrical outlet to convey power to a vehicle's block heatercord via the extender 10.

In the illustrated example, the frame 12 is defined entirely orsubstantially by a rectangular mounting plate 22 of horizontallyelongated shape with a set of fastening holes 23 therein at distributedlocations over its surface area. Through these holes 23, the mountingplate can be fastened to a suitable surface of the vehicle's exterior,typically to a front bumper or license plate holder of the vehicle so asto reside near the front engine compartment where the block heaterresides. The installed frame would thus lie horizontally cross-wise tothe vehicle along the front bumper thereof. The multi-directional joint16, which in the illustrated example is a ball-and-socket joint, ismounted to the frame 12 adjacent one end of the horizontally elongatedframe, and carries a first tubular section 24 of the telescopic arm. Thearm of the illustrated embodiment features a second and intermediatetubular section 26 that is of smaller cross-sectional size and isslidably received within the interior of the first tubular section 24. Athird and final tubular section 28 of the illustrated embodiment definesthe distal end 14 a of the arm 14 and is of even smaller cross-sectionalarea, and is slidably received within the interior of the intermediatetubular section 26. It will be appreciated that the number oftelescopically mated sections within the arm may vary within the scopeof the present invention.

The electrical plug 18 of the extender 10 is carried on the finaltubular section 28 by a flexible cord 30 that has an internal endreceived inside the final tubular section 28. An external end of theflexible cord 30 carries the electrical plug outside the telescopic arm14 beyond the distal end 14 a thereof. In the illustrated embodiment,the distance by which the flexible cord 30 extends from the finaltubular section 28 of the arm 14 is adjustable. Adjustment of the cord'sprojecting distance form the distal end of the arm is performed bypulling on the electrical plug 18 in order to draw it further outwardfrom the arm, or pushing on the plug or the externally exposed portionof the flexible cord to displace more of the cord back into the finalsection of the arm.

In a fully collapsed state of the arm 14, with an entirety or nearentirety of the intermediate section 26 retracted inside the firstsection 24 and an entirety or near entirety of the final section 28retracted inside the intermediate section 24, the overall length of thearm between its joint-mounted proximal end 14 b and its opposingcord-carrying distal end 14 a is shorter in length than the mountingplate 22 of the frame 12. With the flexible cord 30 also fully retractedinto the final section 28 of the arm 14, thus holding the electricalplug 18 against the distal end 14 a of the arm, the combined length ofthe arm, cord and plug from the joint-mounted proximal end 14 b of thearm 14 to the blade tips of the electrical plug 18 is also shorter inlength than the mounting plate of the frame 12, as shown in FIG. 1.

Arm support tabs 32 a, 32 b project from the mounting plate 22 of theframe 12 on the same side thereof at which the arm 14 is mounted by thejoint 16 in order to stabilize the arm 14 when in a stowed positionagainst or closely adjacent the mounting plate when the extender is notin use. The illustrated example includes upper and lower support tabs 32a, 32 b situated above and below the stowed arm 14 to respective blockupward and downwardly swinging of the arm 14 from its stowed positionlying horizontally along the frame in paralleled relation to themounting plate thereof. Each support tab 32 a, 32 b may be a resilientsnap tab with a catch at the outer end thereof for hooking over the topor bottom edge of a front face of the first tubular section 24, wherebythe support tabs 32 a, 32 b also block lateral swinging of the arm 14out its stowed position against or closely adjacent the mounting plate22 of the frame.

A female electrical socket 36 is mounted to the end of another flexiblecord 38 that is partially received in a cord housing 40, which in turnis affixed to the mounting plate 22 of the frame, for example in aposition running along a top edge thereof. The female electrical socket36 resides outside of the cord housing 40 so as to be accessible to thecompatible male plug of a block heater power cord. In the illustratedexample, the cord 38 extends from the housing 40 at a distal end thereofsituated furthest from the multi-directional joint 16 that carries thearm 14. From the female electrical socket 36, the cord 38 extendsthrough the housing 40 and then transitions from the housing 40 into thefirst tubular section 24 of the arm 24, for example through themulti-directional joint. This cord 38 has a length that exceeds theminimum length required to reach the first tubular section 24 of the armthrough the housing 40, and this excess cord length is contained withinthe housing 40 in the illustrated example, where only a short fractionallength of the cord reaches externally from the distal end of the housing40 to carry the female socket 36. During installation of the extender,an installer can thus select how much of the excess cord length to pullout from the housing 40 based on the length of cord 38 required to reachfrom the installed position of the housing 40 on the vehicle to the maleplug of the vehicle's block heater power cord. In one embodiment, cord38 is at least 3-feet long. In the summer, the power plug of the blockheater cord can be disengaged from the female socket 36, and the excesscord 38 can be tucked into the housing 40 for tidy storage.

Electrical communication between the female socket 36 and the electricalplug 18 is provided by a set of cooperating conductors, which includethe internal wires of the two flexible cords 30, 38 and also a pluralityof slidingly mated strips and contacts found within the telescopicallymated arm sections 24, 26, 28.

With reference to the cross-section of FIG. 5, the first tubular section24 features two conductive strips 42 a, 42 b respectively lining a pairof longitudinal grooves defined in opposing internal wall surfaces ofthe first tubular section 24. An inner end of the intermediate tubularsection 26 situated inside the first tubular section 24 carries a pairof electrical contacts 44 a, 44 b that project outwardly beyond theperiphery of the intermediate section 26 to ride within the longitudinalgrooves of the first tubular section 24 in sliding contact with theconductive strips 42 a, 42 b thereof. Likewise, the intermediate tubularsection 26 features two conductive strips 42 c, 42 d respectively lininga pair of longitudinal grooves defined in opposing internal wallsurfaces of the intermediate tubular section 26. An inner end of thefinal tubular section 28 situated inside the intermediate tubularsection 26 carries a pair of electrical contacts 44 c, 44 d that projectoutwardly beyond the periphery of the final section 28 to ride withinthe longitudinal grooves of the intermediate tubular section 26 insliding contact with the conductive strips 42 c, 42 d thereof. The finaltubular section 28 also features two conductive strips 42 e, 42 frespectively lining a pair of longitudinal grooves defined in opposinginternal wall surfaces of the final tubular section 28. The inner end ofthe flexible cord 30 situated inside the final tubular section 28carries a pair of electrical contacts 44 e, 44 f that project outwardlybeyond the periphery of the flexible cord 30 to ride within thelongitudinal grooves of the final tubular section in sliding contactwith the conductive strips 42 e, 42 f thereof.

The hot and neutral wires 38 a, 38 b inside flexible cord 38 arerespectively connected to the conductive strips 42 a, 42 b of the firsttubular section 24 of the arm, and the hot and neutral wires insideflexible cord 30 are respectively connected to the conductive contactpads 44 e, 44 f, whereby the hot wires of the two flexible cords 30, 38are connected by hot side conductive strips and contacts 42 a, 44 a, 42c, 44 c, 42 e, 44 e and the neutral wires of the two flexible cords 30,38 are connected by neutral side conductive strips and contacts 42 b, 44b, 42 d, 44 d, 42 f, 44 f. Though not revealed in the cross-section ofFIG. 5, for example due to positioning on the cut-away walls of thetubular sections, a third conductive strip is preferably provided insideeach tubular section 24, 26, 28 and slidingly mated with a respectivethird contact pad on the next tubular 26, 28 section or cable 30. Theground wire of the cord 18 is connected to the third conductive trip ofthe first tubular section 24. This third set of mating strips andcontact pads provides a conductive ground path from the ground pin ofthe electrical plug 18 to the ground wire of the cord 18. Thisestablishes electrical communication between the ground pin of theelectrical plug 18 and the ground socket contact of the femaleelectrical socket 36 in order to allow grounding of the block heatercord.

Plugging of the male plug of a vehicle's block heater cord into theextender's female socket 36 and plugging of the extender's electricalplug 18 into an electrical outlet of a mains power supply will thus forma closed circuit between the mains power supply and the block heater toprovide power thereto. The block heater cord is plugged into theextender's female socket 36 once, and then any time use of the blockheater is required, the user simply one-handedly swings theextendable/retractable arm 14 out from its stowed position against themounting plate 22 of the frame 12 and points the distal end 14 a towardthe nearest mains power electrical outlet. With the arm deployed outfrom its storage position, the user pulls the electrical plug 18 of theextender toward the mains power electrical outlet, thereby extending theplug 18 slightly from the arm 14 via the extendable cord 30 and alsoextending the telescopic arm until sufficient arm length is achievedfrom the joint 16 to mate the electrical plug 18 with the mains powersocket and thereby energize the block heater. To de-energize the blockheater when use of the vehicle is again required, the reverse action cansimply be performed on a similar one-handed basis, by pulling theelectrical plug 18 out from the mains power electrical socket, andpushing the electrical plug 18 or distal end 14 a of the arm 14 backtoward the joint-carried proximal end 14 b of the arm to telescopicallycollapse the arm and the arm-carried cord 30. The collapsed arm is thenswung back into its stowed position against or closely adjacent theframe 12.

Using the extender of the present invention, there's no need forretrieval of the cord from the vehicle interior, for unwinding orunraveling of a coiled or tangled extension cord, or for two-handedmating of an extension cord with the block heater power cord followed bya separate plugging of the extension cord into to the mains powerelectrical outlet.

The illustrated embodiment includes a plug protecting cover 46 hinged tothe mounting plate 22 of the frame 12 at the distal end thereof oppositethe arm-carrying joint 16. The cover 46 is movable between theillustrated open position reaching longitudinally outward from thisdistal end of the mounting plate 22 in generally parallel relationthereto, and a closed position at least partially concealing theelectrical plug 18 when the arm 14 is in the stowed position.

FIG. 4 shows an optional warning unit 48 that is separate from the mainextender unit shown in FIGS. 1 to 3. The warning unit 48 is to be placedwithin the interior passenger cabin of the vehicle to provide a driverwith a warning signal when the electrical plug 18 of the main extenderunit 10 is plugged into a mains power electrical outlet. In embodimentsincluding this warning unit 48, the main extender unit features awireless transmitter, for example wired within the same conductivecircuit of the extender through which the block heater is energized sothat the wireless transmitter is likewise powered by the mains powersupply when the extender is plugged into the mains power electricaloutlet. When activated by such connection to the mains power supply, thetransmitter sends a wireless signal to the warning unit 50 inside thepassenger cabin of the vehicle, in response to which the warning unitactivates a warning indicator, such as a warning light 52 and/or audiblewarning alarm 54. This way, the driver is reminded that the block heaterextender is still plugged in before they inadvertently drive away fromthe mains power socket, and risk damage to the extender and/or thevehicle.

The warning unit 50 may be powered by a dedicated on-board battery, e.g.lithium battery, but in the illustrated embodiment is instead powered bythe vehicle's electrical system, for example by way of a male 12Vconnector 52 configured to mate with a 12V auxiliary power outlet of thevehicle. Alternatively, the warning unit 50 may include a USB cablecompatible with 5V USB ports commonly found on modern vehicles. Thewarning unit may come with one or more suction cup mounts for couplingto a windshield, window, dashboard or other smooth flat surface insidethe vehicle's passenger cabin.

Some vehicles are configured to provide power through auxiliary powerports only when the vehicle's ignition is on, in which case addedbenefit is realized by the fact that the warning unit 50 only drawspower once the vehicle is started up, and thus does not drain thevehicle battery unnecessarily at times when driver-detectable warning ofthe vehicle's plugged in status is unnecessary. By using wirelesstransmission of the warning signal, the warning indicator can be locatedinside the vehicle where it is most likely to be noticed by the driver,and yet routing of wires between the vehicle's passenger cabin and theextender's exterior mounting location is avoided.

In the alternate scenario where the warning unit relies on a dedicatedbattery rather than the vehicle for power, the warning unit preferablyincorporates a low-battery warning indicator. This may take the form ofanother warning light, preferably of a different illuminated colour thanthe main warning light 52 to ensure distinction between the two. LEDsare preferably used as the warning lights to minimize energy consumptionby the warning unit.

In addition to the wireless warning functionality, the extender may alsoincorporate a timer function by which a user can program a time delayfunction. Such functionality enables use of the extender in a time-delaymode in which the block heater is only energized after a selected periodof time has elapsed from when the extender is plugged into the mainspower electrical outlet. In one embodiment, the user can program orselect between delay periods ranging between zero and twelve hours.Selection or programming of a “zero” time delay interval operates theextender in an “always on” mode rather than in the time-delay mode. Inembodiments employing both the warning and timer functionality, meaningthat the block heater is not necessarily energized at any given timedespite a plugged in status with the mains power electrical outlet, thetransmitter may be arranged to always transmit regardless of whether thetimer has energized the block heater branch of the circuit. This way,the driver is warned of the plugged-in status of the extender regardlessof the energized or de-energized status of the block heater, ascontrolled by the timer.

It will be appreciated that the novel use of an externally mounted blockheater cord extender with a separate internally located alarm unit neednot necessarily be limited to a telescopic-arm extender of the typeshown in described herein, as the unique wireless warning unit 50 of thepresent invention could likewise be paired with a coil-based orreel-based block heater cord extender in which theextendable/retractable extension of the block heater's power cord is acoiled or reel-mounted extension cord, rather than a telescopicallyextendable arm.

Since various modifications can be made in my invention as herein abovedescribed, and many apparently widely different embodiments of samemade, it is intended that all matter contained in the accompanyingspecification shall be interpreted as illustrative only and not in alimiting sense.

The invention claimed is:
 1. A block heater cord extender for connectinga power cord of a vehicle's block heater to an electrical outlet, saidextender comprising: a frame for mounting to the vehicle; a femaleelectrical socket carried on the frame for receiving a male plug of thepower cord of the vehicle's block heater; an extendable/retractable armhaving a proximal end movably mounted to the frame, and a distal endsituated opposite the proximal end, the arm being extendable andretractable to expand and reduce an overall length of said arm betweenthe proximal and distal ends thereof; an electrical plug carried on thearm at or proximate the distal end thereof, said electrical plug beingconfigured to mate with an electrical outlet of a mains power supply;and a circuit comprising electrical conductors connected between thefemale electrical socket and the electrical plug to enable transmissionof power between the mains power supply and the block heater when thepower cord of the vehicle's block heater is mated with the femaleelectrical socket of the extender and the electrical plug of theextender is mated with the electrical outlet of the mains power supply.2. The block heater cord extender of claim 1 wherein the arm is movablebetween a storage position retracted against or adjacent the frame and adeployed position reaching outwardly from the frame.
 3. The block heatercord extender of claim 1 wherein the arm is pivotable about twodifferent axes for both elevational and lateral positional adjustment ofthe arm, by which a user can aim the distal end of the arm toward theelectrical outlet of the mains power supply.
 4. The block heater cordextender of claim 1 wherein the electrical plug is carried on the arm bya flexible cord.
 5. The block heater cord extender of claim 4 whereinsaid flexible cord is extendable and retractable from the distal end ofthe arm.
 6. The block heater cord extender of claim 5 wherein saidflexible cord carries a pair of electrical contacts at an internal endthereof disposed inside a hollow interior of the arm, and the conductorscomprise a pair of conductive strips defined within the hollow interiorof the arm along which the pair of electrical contacts are slidableunder pulling or pushing of the flexible cord from or back into thehollow interior of the arm.
 7. The block heater cord extender of claim 1wherein the arm comprises multiple sections engaged together in asliding manner for sliding extension and retraction of the sectionsrelative to one another in a longitudinal direction of the arm, and theelectrical conductors comprise, for each pair of adjacent sections, aconductive strip lying in the longitudinal direction on one of saidadjacent sections and a respective electrical contact carried on theother of said adjacent sections in sliding contact with said conductivestrip.
 8. The block heater cord extender of claim 7 wherein theelectrical conductors comprise, for said each pair of adjacent sections,a second conductive strip on said one of the adjacent sections, and asecond electrical contact and said other of the adjacent sections. 9.The block heater of claim 8 wherein said flexible cord is extendable andretractable from the distal end of the retractable arm, and theconductors comprise another pair of electrical contacts carried by theflexible cord at an internal end thereof disposed inside a terminaltelescopic section of the arm that defines the distal end thereof, andanother pair of conductive strips that are defined within the terminaltelescopic section and along which said another pair of electricalcontacts are slidable under pulling or pushing of the flexible cord fromor back into the last telescopic section.
 10. The block heater cordextender of claim 8 wherein each conductive strip is located internallyof said one of said adjacent sections.
 11. The block heater cordextender of claim 8 wherein both of said conductive strips are definedon opposing surfaces of said one of said adjacent sections, and both ofsaid conductive contacts project from opposite sides of the other ofsaid adjacent sections.
 12. The block heater cord extender of claim 7wherein each conductive strip is recessed in a groove.
 13. The blockheater cord extender of claim 1 comprising arm supports projecting fromthe frame to support the arm when stowed against or adjacent the frame.14. The block heater cord extender of claim 1 wherein the arm comprisesa plurality of telescopically mated sections by which telescopiccollapse and extension of said sections adjusts the overall length ofthe arm.
 15. The block heater cord extender of claim 1 in combinationwith a separate warning unit for placement inside the vehicle, whereinthe circuit comprises a wireless transmitter arranged to be activated bythe mains power supply when the electrical plug is connected thereto,and the separate warning unit comprises a wireless receiver forreceiving an output signal from the wireless transmitter, and a warningindicator activated by receipt of said output signal to warn a vehicleoperator that the block heater cord extender is plugged into said mainspower supply.
 16. The block heater cord extender of claim 15 whereinsaid at least one warning indicator comprises an indicator light. 17.The block heater cord extender of claim 15 wherein said at least onewarning indicator comprises an audible alarm.
 18. A block heater cordextension system for connecting a power cord of a vehicle's block heaterto an electrical outlet, said system comprising: a block heater cordextender comprising: a frame for mounting to the vehicle; a femaleelectrical socket carried on the frame for receiving a male plug of thepower cord of the vehicle's block heater; an extendable/retractableextension carried by the frame; an electrical plug carried on theextension and configured to mate with an electrical outlet of a mainspower supply; a circuit comprising electrical conductors connectedbetween the female electrical socket and the electrical plug through theextendable/retractable extension to enable transmission of power betweenthe mains power supply and the block heater when the power cord of thevehicle's block heater is mated with the female electrical socket of theextender and the electrical plug of the extender is mated with theelectrical outlet of the mains power supply; and a wireless transmitterinstalled in the circuit for activation by the mains power supply whenthe electrical plug is connected to said mains power supply; and aseparate warning unit for placement inside the vehicle and comprising awireless receiver for receiving an output signal from the wirelesstransmitter when activated, and at least one warning indicator activatedby receipt of said output signal to warn a vehicle operator that theblock heater cord extender is plugged into said mains power supply. 19.The block heater cord extender of claim 18 wherein said at least onewarning indicator comprises an indicator light.
 20. The block heatercord extender of claim 18 wherein said at least one warning indicatorcomprises an audible alarm.